#define _CRT_SECURE_NO_WARNINGS  1
#pragma warning(disable:6031)
#include<stdio.h>
int main()
{
	FILE* pf = fopen("test.txt", "w");
	if (pf == NULL)
	{
		printf("err !");
		return 1;
	}
	fprintf(pf, "Hello World !\n");
	fclose(pf);
	pf == NULL;
	return 0;
}
